Reload guard.yaml without losing the bounties

systemctl reload guard, guard reload or SIGHUP reads the configuration
again: a watch keeps its bounties and counts under the same name and
takes its new settings at once; its source starts again only if it
changed; watches gone stop, new ones start; a file with a mistake is
refused. The Housecarl connection, state, socket and log wait for a
restart, and guard reload says so.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/config/example.yaml

@@ -1,6 +1,6 @@
-# Guard's configuration (docs/configuration.md). Guard reads it when it
-# starts: systemctl restart guard after a change, and 'guard check' to
-# check it first.
+# Guard's configuration (docs/configuration.md). After a change,
+# 'systemctl reload guard' (or 'guard reload') puts it to work and keeps
+# the bounties; 'guard check' checks it first.
 
 # Housecarl, which does the banning. Give Guard a token for its ban list
 # alone; on the firewall: